Statement A: In Mn₂O₇, oxidation state of Mn is +7, which is the highest oxidation state of manganese. Hence, correct.
Statement B: Oxygen stabilizes higher oxidation states of transition metals by forming multiple (pπ–dπ) bonds. Hence, correct.
Statement C: Mn₂O₇ is a covalent oxide and is the anhydride of permanganic acid (HMnO₄). Hence, incorrect.
Statement D: Structure of Mn₂O₇ contains two MnO₃ units linked by one bridging oxygen atom. Hence, correct.
Correct statements: A, B and D only
Correct Option: B